There is a need for sample holders that are thermally efficient in the manner in which heat is delivered to a contained sample, removed from a contained sample, or both. This is particularly acute in the field of polymerase chain reaction amplification of nucleic acid (e.g., DNA amplification). In such applications, samples are exposed to a dynamic heating and cooling protocol. Successful amplification often relies upon time dependent heat transfer. As a result, the efficiency of such operations can be limited when the mass, volume, or length of heat transfer of a sample is such that it impedes heat transfer within it, and to and from it.
One approach to sample tubes for amplification of nucleic acid has been to employ glass capillaries. While useful, the risk of breakage during use and the inability to deform such glass tubes during an amplification process make the use of glass capillaries an undesirable option. Another approach has been to employ polymeric sample vessels. However, the polymeric material may not provide sufficient heat transfer to substances within the tubes and may also fail to provide sufficient elasticity to be compressed as necessary during the amplification process. Examples of such polymeric and glass sample holders include those in U.S. Pat. Nos. 5,225,165; 5,353,186; 5,571,479; 5,604,101; 5,721,136; 5,863,791; 5,958,349; 6,015,534; 6,159,727; 6,312,886; 6,783,025; 7,255,833; and 7,749,452.
There is thus a need for an improved polymeric sample tube that provides for both sufficient heat transfer and sufficient elasticity for use in amplification processes that require compression of the tube during use.